Interstitial lung disease Flashcards
What is an interstitial lung disease?
Any disease effecting the lung interstitium- the alvioli and terminal bronchi
What type of pattern would you see in spirometry for a patient with interstitial lung disease?
Restrictive pattern because gas exchange is effected
What are the common symptoms of ILD?
Breathlessness and DRY cough
ILD can be acute, episodic or chronic. What are the 4 types of ILD?
1) ILD of known cause
2) Idiopathic interstitial pneumonia (IIP)
3) Granulomatous ILD
4) Other forms of ILD
What are the causes of ‘known cause ILD’?
Rheumatoid arthritis, collagen vascular disease, drugs and association with other diseases
What are the 2 types of idiopathic interstitial pneumonia?
Idiopathic pulmonary fibrosis (IPF) and not IPF
What causes granulomatous ILD?
Sarcoidosis and hypersensitivity pneumonitis
What is sarcoidosis?
A type 4 hypersensitivity reaction of unknown causes that causes granulomatous ILD
Sarcoidosis can be a systemic disease. What are the most common system involvements?
Lung and hyler lymph nodes
joints, liver, kidneys, brain, nerves and heart
What type of granuloma forms in sarcoidosis?
Non caseating granuloma
Sarcoidosis is more common in smokers. True or false?
False
Sacoidosis is more common in non smokers
What are the symptoms of acute sarcoidosis?
Erythema nodosum Bilateral hyler lymphadenopathy Arthritis Uveitis and parotitis (inflammation of the middle layer of eye and parotid gland) Fever and malaise
What are the symptoms of chronic sarcoidosis?
Lung infiltrates- alviolitis Skin infiltrates Peripheral lymphadenopathy Hypercalemia Other organ involvement
What are the differential diagnosis for sarcoidosis?
TB, Lymphoma, Carcinoma and fungal infection
What investigations should you do if you suspect sarcoidosis?
CXR- specifically bilateral hyler lymph nodes
CT scan- peripheral nodular infiltrates
Tissue biopsy- non caseating granuloma (multinucleated giant cells)
Pulmonary function- spirometry and TLCO
Bloods: ACE levels- monitoring not diagnosis (test for granuloma)
Raised calcium
Increased inflammatory markers
It is common to have a relapse of sarcoidosis. True or false?
True- must monitor CXR and pulmonary function for years
WHat is the treatment for acute sarcoidosis?
No treatment unless vital organs are involved and then steroids are given. Its self limiting
What is the treatment for chronic sarcoidosis?
Oral steroids needed for 1-2 years
If you stop steroids and then get a relapse you may need immunosupressive drugs such as methotrexate or azathioprine.
What are the pulmonary function restrictive signs?
Low FEV1 and low FVC
High/normal FEV1:FVC ratio
Low TLCO
What is hypersensitivity pneumonitis?
Type 3 hypersensitivity reaction where immune complexes are deposited in the lungs leading to alviolitis
What is the aetiology of hypersensitivity pneumonitis?
Mostly occupational: farmers lung, bird fancier’s lun, cheese workers lung.
Idiopathic in 30% of cases
Can hypersensitivity pneumonitis be acute or chronic?
Yes- depends on the length of exposure.
Little and often- chronic
All at once- acute
What are the signs of acute hypersensitivity pneumonitis?
Cough, breathlessness, fever, maialgia
Symptoms occur several hours after exposure
Crackles and hypoxia
What is the treatment for acute hypersensitivity pneumonitis and what would you see on a CXR?
Widespread pulmonary infiltrates on CXR
Treatment = oxygen, steroids and antigen avoidance
What are the signs of chronic hypersensitivity pneumonitis?
Repeated low dose antigen exposure over years
Progressive breathlessness and cough
Crackles in chest
What would you expect to see on a CXR and pulmonary function tests of someone with chronic hypersensitivity pneumonitis?
CXR = pulmonary fibrosis in the upper zones
Pulmonary function is restrictive
What is a diagnosis of chronic hypersensitivity based on?
History of exposure and precipitins- measuring the IgG antibody to the antigen in question
What is the treatment for chronic hypersensitivity pneumonitis?
Remove antigen exposure and oral steroids
Is idiopathic pulmonary fibrosis an inflammatory condition and is it more common in smokers?
It is not an inflammatory condition but is more common in smokers.
What is the characteristics of IPF?
Lung is repairing itself when there is nothing to repair => scar tissue
Looks similar to pulmonary fibrosis of known causes
Which drugs can cause IPF?
Methatrexate, Nitrofuratonin, Ameodarone, Bleomycin, Penicillamine, Busulphan
What is the presentation, examination findings and investigations for IPF?
Presentation = progressive breathlessness over several years and dry cough Examination = Clubbing and bilateral crackles Investigations = Pulmonary function (restrictive), CXR (bilateral infiltrates) CT (Reticulondular fibrotic shadowing worse at the base and periphery. Traction bronchiectasis and honey combing)
What would you expect to see on a CT scan of someone with IPF?
Reticulondular fibrotic shadowing worse at the base and periphery. Traction bronchiectasis and honey combing.
If the presentation is atypical a lung biopsy should be done
What are the differential diagnoses of IPF?
Occupational disease, connective tissue disease, left ventricular failure, sarcoidosis, hypersensitivity pneumonitis
What is the treatment for IPF?
Steroids and immunosupressants do NOT change the course of the disease
Pirfenidone and Nitedanib slow down disease progression but are expensive
Oxygen if hypoxic
Lung transplant if under 65
Give 4 examples of occupational lung disease
Bariosis, Silicosis, Coal workers pneumoconiosis and asbestosis
What is simple pneumoconiosis?
No patient symptoms or lung function impairment, just an CXR abnormality
What is complicated pneumoconiosis?
Progressive massive fibrosis
Restrictive pattern and breathlessness
What is Caplan’s syndrome?
Rheumatoid pneumoconiosis
Patient with rheumatoid arthritis also exposed to coal dust
What are the 4 types of pleural disease due to asbestos exposure?
Only one fibre needed
1) Benign pleural plaques- asymptomatic
2) Acute asbestos pleuritic- fever, pain, bloody pleural effusion
3) Pleural effusion and diffuse pleural thickening- restrictive inpariment
4) Mesothilioma- fatal within 2 years
Can asbestos cause pulmonary fibrosis?
Yes if heavy, prolonged exposure. Called Asbestosis.
Diffuse pulmonary fibrosis and restrictive defect.
Asbestos fibres in biopsy and sputum
How does asbestos exposure effect the risk of bronchial carcinoma in smokers?
Multiplies the risk
What is within the pulmonary interstitium?
Alveolar ling cells- types 1 and 2 pneumocytes
Thin elastin rich connective tissue containing capillary blood vessels
What are the characteristics of early and late stage ILD?
Early = alveolitis- injury with inflammatory cell infiltration Late = diffuse fibrosis
Give 2 biopsies often used in the diagnosis of ILD?
Transbronchial biopsy- forceps used at bronchoscopy
Thoracoscopic biopsy- more invasive but more reliable and generates more tissue
What are the pathological changes you may see in IPF?
Peripheral and basal fibrosis- honey combing and thickening
Inflammatory component is variable
Terminally, lung structures are replaced by dilated spaces surrounded by fibrous walls
What are the pathological changes you may see in hypersensitivity pneumonitis?
Inflammatory interstitial expansion
Granulomas with multi nucleated giant cells, infiltration
NO necrosis
What are the pathological changes you may see in sarcoidosis?
Granulomas with multi nucleated giant cells. NO necrosis and NO destruction of surrounding tissues
If it becomes chronic you will see fibrosis
Connective tissue diseases such as lupus and rheumatiods disease can cause ILD. What pathological changes may you see in ILD caused by connective tissue disorders?
Interstitial fibrosis
Pleural effusions
Rheumatoid nodules occurring subcutaineously and in deep tissues
What are the pathological changes you may see with pneumoconiosis?
Nodular scarring and fibrous reaction to mineral dust inhaled
Pneumoconiosis is due to the inhalation of mineral dust. What does the disease depend on?
1) particle size must be between 1-5 microns
2) Reactivity of the particle
3) Clearance of the particle
4) Host response
Which asbestos particle is safer and which is more dangerous?
Serpentine (curved) = relatively safe
Amphibole (straight) = highly dangerous
How are asbestosis bodies identified at post mortem?
By incinerating the lung tissue
